1. Field of the Invention
Diagnostic radiopharmaceuticals have been developed which have affinity for either the polygonal or reticuloendothelial cells of the liver. Iodinated rose bengal was a common hepatocyte imaging agent but suffered from having a long nuclear half-life and high energy nuclear emissions. More recently, technetium labeled hepatobiliary imaging agents have been developed but suffer from having short hepatocyte residence times and rapid excretion into the biliary tract. Among their shortcomings for liver imaging are visualization of the gall bladder and upper duodenum after maximal liver concentration is achieved, inability to obtain multiple views of the liver, wide patient variation in urinary excretion and reduced hepatic extraction and delayed biliary excretion in jaundiced patients.
The most common agent for clinical scintigraphic evaluation in the liver is Tc-99m-sulfur colloid (Tc-SC), which while finding wide use, lacks hepatic specificity and therefore has an inadequate ability to differentiate hepatic disease states.
2. Brief Description of the Prior Art
Krantz et al., Biochemistry 15 3963 (1976) describes a preparation of neoglycoproteins, particularly .alpha.-amylase, hens egg lysozyme and bovine serum albumin with D-galactose and D-glucose. Vera, Krohn and Stadalnik presented a paper entitled "Radioligands that Bind to Cell-Specific Receptors: Hepatic Binding Protein Ligands for Hepatic Scintigraphy," at the proceedings of the Second International Symposium on Radiopharmaceuticals, Mar. 19-22, 1979 which describes the use of technetium-99m-galactosyl neoglycoalbumin for use as a radiopharmaceutical for hepatocyte binding. U.S. Pat. No. 4,010,251 reports the use of an asialoglycoprotein for visualizing liver and evaluating biliary function. Patents of interest describing the use of technetium-99m as a medical diagnostic radionuclide are U.S. Pat. Nos. 4,126,669; 4,104,366; 4,094,965; 3,872,226; and 3,466,361.